http://gophp5.org/

I'm a little annoyed to see phpMyAdmin on the list -- I still need to admin a few web sites that run PHP4. 

I don't understand why the PHP developers didn't just add the PHP4 parser into PHP5; this issue could have been resolved a long time ago.  By not supporting PHP4 more directly they slowed the adoption of PHP5 rather than increase it.

I wonder if we'll have to go through all this again with PHP6!